Doxy PEP adherence found to differ by age, gender identity, race, housing status, and PrEP use

SAN FRANCISCO, March 11, 2025–Research presented today at the Conference on Retroviruses and Opportunistic Infections (CROI) by San Francisco AIDS Foundation (SFAF) researchers sheds light into the Doxy PEP “continuum of care” experienced by clients at SFAF’s sexual health clinic Magnet. Among the nearly 7,500 clients indicated for sexually transmitted infection (STI) prevention with Doxy PEP, the percentage of clients reporting consistent use of Doxy PEP was low: only 22%; and drop-offs in adherence were found to vary by age, gender identity, race, housing status, and HIV status.

“Across the Doxy PEP continuum, we found significant disparities by social determinants of health that are known to affect other aspects of PrEP, HIV, and sexual health care,” said Mike Barry, PhD, MPH, Director of Evaluation & Impact at SFAF. “This study showed that people ages 14-29, people who were unstably housed or homeless, Black and African American people, HIV-negative people not using PrEP, and people living with HIV were less likely to start Doxy PEP and use it consistently. We hope that these findings may inform future outreach efforts and client-provider interactions so that communities who may need special considerations receive the support they need.”

“Although we found a significant fall off across the Doxy PEP continuum–with some groups experiencing even greater disparities–we are still seeing a powerful effect of the Doxy PEP roll out,” said Hyman Scott, MD, MPH, Medical director of SFAF. “Sexually transmitted infection rates for syphilis and chlamydia are falling dramatically across San Francisco, likely due to the uptake of Doxy PEP by people who may benefit most from this prevention tool. We are committed to using this research to inform our clinical practices and policy decisions, and continue to track STI rates closely.”

Two years of client records from SFAF’s Magnet clinic from December 2022 to December 2024 were analyzed for the study, with a total of 7,436 clients included with a clinical indication for Doxy PEP use.

The Doxy PEP continuum of care was defined as follows: 1) Indication for Doxy PEP (meets San Francisco Department of Public Health guidelines); 2) Receives a Doxy PEP prescription (prescription included in patient record); Initiation of Doxy PEP (client reports any Doxy PEP use); and, 4) Adherence to Doxy PEP (client reports consistent Doxy PEP use <72 hours after sexual encounters since prior visit).

Of the 7,436 clients indicated for Doxy PEP, 59% (4,369) received a prescription, 61% (2,651) of those individuals reported taking one or more doses, and 61% (1,627) of individuals who took one or more doses reported high adherence (22% of all clients indicated for Doxy PEP).

There were notable differences in prescription receipt by group, with fewer prescriptions among younger individuals, transgender men, unhoused and unstably housed individuals, and HIV-negative individuals not using PrEP. Transgender women were more likely to be prescribed Doxy PEP than individuals of other gender identities. Younger individuals, Black and African American individuals, unhoused or unstably housed individuals, and people living with HIV were less likely to initiate Doxy PEP once prescribed. Young individuals, San Francisco residents, and people living with HIV were less likely to report high adherence if they took Doxy PEP at least once.

Younger individuals ages 14-29, Black and African American clients, people who reported unstable housing or homelessness, and clients living with HIV were less likely to report high adherence.

“We approached this research with the goal of informing our provision of sexual health care,” said Barry. “Knowing the social determinants of health that affect Doxy PEP uptake and adherence will directly inform our ability to intervene and tailor prevention services, so that all communities are able to benefit equally from this prevention measure.”

# # #

Barry, M. P., Bena, J., Roman, J. & Scott, H., The Doxy-PEP Continuum Among Patients Receiving Care at a Sexual Health Clinic in San Francisco. CROI, 2025: Abstract 164.